The present disclosure relates to an externally adjustable latch for use in latching doors or moveable panels to a corresponding structure.
A variety of latches are available for closing doors and maintaining panels in position against structures. One version of such a latch attaches to the panel to be retained and has an extending bolt portion which abuts a corresponding internal surface of the structure surrounding the panel. The most basic form of this latch does not have any adjustability and cannot be adjusted to a variable preload. Preload can only be achieved by a very basic system of adding shims between the bolt and the corresponding structure.
Another version of latches have been developed which allows some degree of adjustability. In this prior art device, an adjustable screw is provided on the bolt end which abuts the corresponding structure. The adjustable portion is not easily adjustable. The adjustment must be made internally, on the inside of the panel once it is closed and the latch is engaged. This of course requires somebody to adjust the mechanism from the inside and another person to open and close the latch on the outside. This can be a problem because the interior surface may not have sufficient room to reach the adjustment portion or to properly make adjustments. Alternatively, the latch can be adjusted by opening and making incremental adjustments to the latch, closing the panel and checking the fit, reopening the panel making adjustments to the latch. This process can be quite labor intensive and may not provide a suitably tight latching of the panel against the structure.
It should be noted that variable load is not achievable in the latch without adjustment. This is also true of the latch which has the adjustment mechanism described above requiring numerous adjustment steps. It is common for there to be multiple latches on a single panel or door. The problems discussed here and above with the prior art are complicated when multiple latches are used on a panel to secure different portions of a particular edge or different edges.
One of the problems that results when the panels are not adjustable or not properly adjusted is that vibration of the panel can occur. The gaps or spacing associated with each latch provides some degree of movement in the panel. The movement can be induced by pressure differential between the interior and exterior pressures on the panel or door, as well as vibrations transmitted to the panel. Vibrations transmitted to the panel occur on aircraft when the panels are used in structures which have vibrations such as coverings for engine and other mechanical systems.
An additional issue which arises with prior art devices is that lock wire or jam nuts are required to be attached to the adjustable bolts thereby requiring additional labor to install the lock wire or jam nut as well as to remove it when making additional adjustments. For example, when adjusting the prior art adjustment screws, the adjustments are made as noted above. Once the desired adjustment is achieved, the lock wire or jam nut is attached to the adjuster to maintain the desired adjustment. As often happens with such adjustable structures, when further adjustment is required, the lock wire or jam nut must be removed. Further adjustment made and then reattachment of the lock wire or jam nut. It should also be noted that adjustment is not easy since it may require two wrenches to adjust the adjustable structure.
The present disclosure envisions an externally adjustable mechanism which is carried on the bolt of a latch. The externally adjustable mechanism has an exterior portion which is generally flush-mounted relative to the exterior surfaces of the corresponding panel and structure. A small access opening is provided to access the adjustment structure so as to help maintain the aerodynamic design of the flush-mounted latch. The externally adjustable mechanism includes an adjuster which works with a moveable lever. Force is applied to one end of the moveable lever operate on a plunger carried on an opposite end of the lever. The present disclosure allows for controllable external adjustment as well as controllable preloading of the forces on the latch. The adjuster can be controllably preloaded by using a torque-wrench or torque-measuring device to make adjustments to a desired level of force.
Additional features will become apparent to those skilled in the art upon consideration of the following detailed description of drawings.